Managing Comments
=================

Comment management includes updating, deleting and approving comments. These operations are implemented as actions in the `CommentController` class.


Updating and Deleting Comments
------------------------------

The code generated by `Gii` for updating and deleting comments remains largely unchanged.


Approving Comments
------------------

When comments are newly created, they are in pending approval status and need to be approved in order to be visible to guest users. Approving a comment is mainly about changing the status column of the comment.

We create an `actionApprove()` method in `CommentController` as follows,

~~~
[php]
public function actionApprove()
{
	if(Yii::app()->request->isPostRequest)
	{
		$comment=$this->loadModel();
		$comment->approve();
		$this->redirect(array('index'));
	}
	else
		throw new CHttpException(400,'Invalid request...');
}
~~~

In the above, when the `approve` action is invoked via a POST request, we call the `approve()` method defined in the `Comment` model to change the status. We then redirect the user browser to the page displaying the post that this comment belongs to.

Of course, we also need to create the `approve()` method in the `Comment` model. It is as follows,

~~~
[php]
public function approve()
{
	$this->status=Comment::STATUS_APPROVED;
	$this->update(array('status'));
}
~~~

Here we are simply setting the status property of the comment to `approved` as defined by the status constants in the `Comment` class:

~~~
[php]
class Comment extends CActiveRecord
{
	...
	
	const STATUS_PENDING=1;
	const STATUS_APPROVED=2;
	
	..
}
~~~

and then calling the `update()` method to save this newly set property to the database.
	
We also modify the `actionIndex()` method of `CommentController` to show all comments. We would like to see comments pending approval show up first.

~~~
[php]
public function actionIndex()
{
	$dataProvider=new CActiveDataProvider('Comment', array(
		'criteria'=>array(
			'with'=>'post',
			'order'=>'t.status, t.create_time DESC',
		),
	));

	$this->render('index',array(
		'dataProvider'=>$dataProvider,
	));
}
~~~

Notice that in the above code, because both `tbl_post` and `tbl_comment` have columns `status` and `create_time`, we need to disambiguate the corresponding column reference by prefixing them with table alias names. As described in [the guide](http://www.yiiframework.com/doc/guide/database.arr#disambiguating-column-names), the alias for the primary table in a relational query is always `t`. Therefore, we are prefixing `t` to the `status` and `create_time` columns in the above code to indicate we want these values taken from the primary table, `tbl_comment`.

Like the post index view, the `index` view for `CommentController` uses [CListView] to display the comment list which in turn uses the partial view `/wwwroot/blog/protected/views/comment/_view.php` to display the detail of each individual comment. We will not go into details here. Interested readers may refer to the corresponding file in the blog demo `/wwwroot/yii/demos/blog/protected/views/comment/_view.php`.

